HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) References Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by BOWMAN, J. R. Articles by KISSLINGER, C. Search for Related Content GeoRef GeoRef Citation

Seismicity associated with a cluster of earthquakes of m_b 4.5 near Adak, Alaska: Evidence for an asperity?

CIRES UNIVERSITY OF COLORADO/NOAA, BOULDER, COLORADO 80309
DEPARTMENT OF GEOLOGICAL SCIENCES UNIVERSITY OF COLORADO, BOULDER, COLORADO 80309

Abstract

An area of the main thrust zone south of Adak, Alaska, in the central Aleutian island arc is characterized by clustering of hypocenters of earthquakes of m_b 4.5 and by low b-value relative to the rest of the thrust zone. The location and dimension of two of these clusters has been constant during 15 yr of teleseismic and 9 yr of local monitoring. Six earthquakes of m_b 4.5 have occurred in one of the cluster areas in the past 3 yr in contrast to two earthquakes of m_b 4.1 in the previous 6 yr. The concentration of moderate-sized earthquakes and low b-value may reflect a stress concentration at an asperity on the interface between the Pacific and North American plates. The recent activation of this asperity may indicate preparation for a larger earthquake. A change of local (SV/P)_z amplitude ratios of small earthquakes before two earthquakes of m_b 4.5 may indicate a change of focal mechanism reflecting a reorientation of stress around the asperity prior to larger earthquakes.

This article has been cited by other articles:

				C. Kisslinger and B. Kindel A comparison of seismicity rates near Adak Island, Alaska, September 1988 through May 1990 with rates before the 1982 to 1986 apparent quiescence Bulletin of the Seismological Society of America, October 1, 1994; 84(5): 1560 - 1570. [Abstract] [PDF]

				C. KISSLINGER An experiment in earthquake prediction and the 7 May 1986 Andreanof Islands earthquake Bulletin of the Seismological Society of America, February 1, 1988; 78(1): 218 - 229. [Abstract] [PDF]

				F. SCHERBAUM and C. KISSLINGER Coda Q in the Adak seismic zone Bulletin of the Seismological Society of America, April 1, 1985; 75(2): 615 - 620. [PDF]